District of Columbia police say they are investigating an incident in which NBC News reporter David Gregory displayed what he described as a high-capacity ammunition magazine on "Meet the Press."

Gun laws in the nation's capital generally restrict the possession of high-capacity magazines, regardless of whether the device is attached to a firearm.

"NBC contacted [the Metropolitan Police Department] inquiring if they could utilize a high capacity magazine for their segment. NBC was informed that possession of a high capacity magazine is not permissible and their request was denied. This matter is currently being investigated," police spokeswoman Gwendolyn Crump said in a written statement. She declined to comment further on the investigation.

While interviewing National Rifle Association CEO Wayne LaPierre for Sunday's program, Gregory held an object, apparently as a prop to make a point, and said it was a magazine that could hold 30 rounds.

"Here is a magazine for ammunition that carries 30 bullets. Now, isn't it possible if we got rid of these, if we replaced them and said, 'Well, you can only have a magazine that carries five bullets or ten bullets,' isn't it just possible that we could reduce the carnage in a situation like Newtown?'" Gregory asked, referring to the Dec. 14 mass shooting at an elementary school in Connecticut.

LaPierre replied, "I don't believe that's going to make one difference. There are so many different ways to evade that even if you had that" ban.